linux/kernel, branch v2.6.32.48

Revert "genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlier"

2011-11-09T00:02:23Z

This reverts commit 0f12a6ad9fa3a03f2bcee36c9cb704821e244c40. It causes too many build errors and needs to be done properly. Reported-by: Jiri Slaby Reported-by: Christoph Biedl Cc: Ian Campbell Cc: Rafael J. Wysocki Cc: Jeremy Fitzhardinge Cc: xen-devel Cc: Konrad Rzeszutek Wilk Cc: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlier

2011-11-07T20:32:43Z

commit 9bab0b7fbaceec47d32db51cd9e59c82fb071f5a upstream This adds a mechanism to resume selected IRQs during syscore_resume instead of dpm_resume_noirq. Under Xen we need to resume IRQs associated with IPIs early enough that the resched IPI is unmasked and we can therefore schedule ourselves out of the stop_machine where the suspend/resume takes place. This issue was introduced by 676dc3cf5bc3 "xen: Use IRQF_FORCE_RESUME". Back ported to 2.6.32 (which lacks syscore support) by calling the relavant resume function directly from sysdev_resume). Signed-off-by: Ian Campbell Cc: Rafael J. Wysocki Cc: Jeremy Fitzhardinge Cc: xen-devel Cc: Konrad Rzeszutek Wilk Link: http://lkml.kernel.org/r/1318713254.11016.52.camel@dagon.hellion.org.uk Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

time: Change jiffies_to_clock_t() argument type to unsigned long

2011-11-07T20:32:28Z

commit cbbc719fccdb8cbd87350a05c0d33167c9b79365 upstream. The parameter's origin type is long. On an i386 architecture, it can easily be larger than 0x80000000, causing this function to convert it to a sign-extended u64 type. Change the type to unsigned long so we get the correct result. Signed-off-by: hank Cc: John Stultz [ build fix ] Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

kmod: prevent kmod_loop_msg overflow in __request_module()

2011-11-07T20:32:27Z

commit 37252db6aa576c34fd794a5a54fb32d7a8b3a07a upstream. Due to post-increment in condition of kmod_loop_msg in __request_module(), the system log can be spammed by much more than 5 instances of the 'runaway loop' message if the number of events triggering it makes the kmod_loop_msg to overflow. Fix that by making sure we never increment it past the threshold. Signed-off-by: Jiri Kosina Signed-off-by: Rusty Russell Signed-off-by: Greg Kroah-Hartman

futex: Fix regression with read only mappings

2011-08-29T21:08:07Z

commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae upstream. commit 7485d0d3758e8e6491a5c9468114e74dc050785d (futexes: Remove rw parameter from get_futex_key()) in 2.6.33 fixed two problems: First, It prevented a loop when encountering a ZERO_PAGE. Second, it fixed RW MAP_PRIVATE futex operations by forcing the COW to occur by unconditionally performing a write access get_user_pages_fast() to get the page. The commit also introduced a user-mode regression in that it broke futex operations on read-only memory maps. For example, this breaks workloads that have one or more reader processes doing a FUTEX_WAIT on a futex within a read only shared file mapping, and a writer processes that has a writable mapping issuing the FUTEX_WAKE. This fixes the regression for valid futex operations on RO mappings by trying a RO get_user_pages_fast() when the RW get_user_pages_fast() fails. This change makes it necessary to also check for invalid use cases, such as anonymous RO mappings (which can never change) and the ZERO_PAGE which the commit referenced above was written to address. This patch does restore the original behavior with RO MAP_PRIVATE mappings, which have inherent user-mode usage problems and don't really make sense. With this patch performing a FUTEX_WAIT within a RO MAP_PRIVATE mapping will be successfully woken provided another process updates the region of the underlying mapped file. However, the mmap() man page states that for a MAP_PRIVATE mapping: It is unspecified whether changes made to the file after the mmap() call are visible in the mapped region. So user-mode users attempting to use futex operations on RO MAP_PRIVATE mappings are depending on unspecified behavior. Additionally a RO MAP_PRIVATE mapping could fail to wake up in the following case. Thread-A: call futex(FUTEX_WAIT, memory-region-A). get_futex_key() return inode based key. sleep on the key Thread-B: call mprotect(PROT_READ|PROT_WRITE, memory-region-A) Thread-B: write memory-region-A. COW happen. This process's memory-region-A become related to new COWed private (ie PageAnon=1) page. Thread-B: call futex(FUETX_WAKE, memory-region-A). get_futex_key() return mm based key. IOW, we fail to wake up Thread-A. Once again doing something like this is just silly and users who do something like this get what they deserve. While RO MAP_PRIVATE mappings are nonsensical, checking for a private mapping requires walking the vmas and was deemed too costly to avoid a userspace hang. This Patch is based on Peter Zijlstra's initial patch with modifications to only allow RO mappings for futex operations that need VERIFY_READ access. Reported-by: David Oliver Signed-off-by: Shawn Bohrer Acked-by: Peter Zijlstra Signed-off-by: Darren Hart Cc: KOSAKI Motohiro Cc: peterz@infradead.org Cc: eric.dumazet@gmail.com Cc: zvonler@rgmadvisors.com Cc: hughd@google.com Link: http://lkml.kernel.org/r/1309450892-30676-1-git-send-email-sbohrer@rgmadvisors.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

perf: overflow/perf_count_sw_cpu_clock crashes recent kernels

2011-08-08T17:23:22Z

The below patch is for -stable only, upstream has a much larger patch that contains the below hunk in commit a8b0ca17b80e92faab46ee7179ba9e99ccb61233 Vince found that under certain circumstances software event overflows go wrong and deadlock. Avoid trying to delete a timer from the timer callback. Reported-by: Vince Weaver Signed-off-by: Peter Zijlstra Signed-off-by: Greg Kroah-Hartman

PM / Hibernate: Fix free_unnecessary_pages()

2011-07-13T03:29:26Z

commit 4d4cf23cdde2f8f9324f5684a7f349e182039529 upstream. There is a bug in free_unnecessary_pages() that causes it to attempt to free too many pages in some cases, which triggers the BUG_ON() in memory_bm_clear_bit() for copy_bm. Namely, if count_data_pages() is initially greater than alloc_normal, we get to_free_normal equal to 0 and "save" greater from 0. In that case, if the sum of "save" and count_highmem_pages() is greater than alloc_highmem, we subtract a positive number from to_free_normal. Hence, since to_free_normal was 0 before the subtraction and is an unsigned int, the result is converted to a huge positive number that is used as the number of pages to free. Fix this bug by checking if to_free_normal is actually greater than or equal to the number we're going to subtract from it. Signed-off-by: Rafael J. Wysocki Reported-and-tested-by: Matthew Garrett Signed-off-by: Greg Kroah-Hartman

PM / Hibernate: Avoid hitting OOM during preallocation of memory

2011-07-13T03:29:26Z

commit 6715045ddc7472a22be5e49d4047d2d89b391f45 upstream. There is a problem in hibernate_preallocate_memory() that it calls preallocate_image_memory() with an argument that may be greater than the total number of available non-highmem memory pages. If that's the case, the OOM condition is guaranteed to trigger, which in turn can cause significant slowdown to occur during hibernation. To avoid that, make preallocate_image_memory() adjust its argument before calling preallocate_image_pages(), so that the total number of saveable non-highem pages left is not less than the minimum size of a hibernation image. Change hibernate_preallocate_memory() to try to allocate from highmem if the number of pages allocated by preallocate_image_memory() is too low. Modify free_unnecessary_pages() to take all possible memory allocation patterns into account. Reported-by: KOSAKI Motohiro Signed-off-by: Rafael J. Wysocki Tested-by: M. Vefa Bicakci Signed-off-by: Greg Kroah-Hartman

taskstats: don't allow duplicate entries in listener mode

2011-07-13T03:29:25Z

commit 26c4caea9d697043cc5a458b96411b86d7f6babd upstream. Currently a single process may register exit handlers unlimited times. It may lead to a bloated listeners chain and very slow process terminations. Eg after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of kernel memory is stolen for the handlers chain and "time id" shows 2-7 seconds instead of normal 0.003. It makes it possible to exhaust all kernel memory and to eat much of CPU time by triggerring numerous exits on a single CPU. The patch limits the number of times a single process may register itself on a single CPU to one. One little issue is kept unfixed - as taskstats_exit() is called before exit_files() in do_exit(), the orphaned listener entry (if it was not explicitly deregistered) is kept until the next someone's exit() and implicit deregistration in send_cpu_listeners(). So, if a process registered itself as a listener exits and the next spawned process gets the same pid, it would inherit taskstats attributes. Signed-off-by: Vasiliy Kulikov Cc: Balbir Singh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

PM: Free memory bitmaps if opening /dev/snapshot fails

2011-07-13T03:29:24Z

commit 8440f4b19494467883f8541b7aa28c7bbf6ac92b upstream. When opening /dev/snapshot device, snapshot_open() creates memory bitmaps which are freed in snapshot_release(). But if any of the callbacks called by pm_notifier_call_chain() returns NOTIFY_BAD, open() fails, snapshot_release() is never called and bitmaps are not freed. Next attempt to open /dev/snapshot then triggers BUG_ON() check in create_basic_memory_bitmaps(). This happens e.g. when vmwatchdog module is active on s390x. Signed-off-by: Michal Kubecek Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman